The invention relates to an air diffuser designed to regulate air flow from an underfloor air distribution system.
Underfloor air distribution has gained popularity in work environments due to its design flexibility and reconfiguration capabilities. While early underfloor air distribution systems were designed for spaces housing large computer systems, the increased use of local area networks and telecommunication systems are requiring entire buildings to be designed with underfloor air distribution systems that provide large quantities of cooling air. Also, with the trend to more frequent office reorganization, flexible offices with electrical and mechanical systems that can be easily reconfigured at minimum cost to accommodate personnel and hardware requirements are in increased demand.
Bottom source or underfloor air distribution systems typically include a number of small diffusers that can be moved to accommodate frequent changes in space usage and the resulting changes in ventilation requirements. The diffusers are usually mounted in a raised floor that defines the top surface of a plenum chamber. In other words, the space beneath the floor panels constitutes an enclosed plenum chamber or air space in which the air pressure is greater than in the room or other enclosure to be heated, cooled or ventilated. Air flows from the plenum chamber through the diffusers into the room or other enclosure. For optimal performance, diffusers should expel air in a swirling air pattern with little or no turbulence and, to prevent drafts, relatively low jet velocities. This pattern promotes high induction or entrainment rates that mix unconditioned air within the room with the air being supplied through the diffusers, thereby providing comfortable air movement and eliminating or reducing air stagnation and stuffiness.
One known underfloor air distribution system, produced by Krantz, is an injection molded device consisting of a diffuser grille, a damper, a basket, a trim frame and a retaining frame. The damper is placed within the basket, and the grille is placed on top of the damper. The damper and basket may have slotted side walls so that air flow into the air distributor can be controlled by rotating the damper. The grille may be connected to the damper, for example, with pins which extend from the upper edge of the damper into slots in the grille, so that the damper may be rotated by rotating the grille. The basket is inserted into the trim frame, which is inserted into the retaining frame. The retaining frame, in turn, can be affixed to flooring panels for access to the underfloor air plenum supply. The grille is designed with a circular configuration and has air slots which extend radially from the center of the grille to the outside edge of the grille. The slots can vary in length and width, but have a uniform slope.
The present invention provides a diffuser adapted to regulate air flow from an underfloor air distribution system. In the preferred embodiment, the diffuser has a grille with slots, extending generally outward from the center of the grille, that produce a swirling air flow pattern with high induction. The grille sets on a dust receptacle or basket-shaped housing that is supported by a mounting assembly in the floor. A flow regulator or damper nests inside the housing. Both the housing and the flow regulator have air slots extending through their side walls. Air from the underfloor air plenum passes through these slots into the diffuser and is forced through the helical slots in the grille into the room above the diffuser. The air flow rate can be adjusted by rotating the flow regulator within the housing so that the slots in the flow regulator are either in or out of registry with the slots in the housing. The flow regulator has a series of pins that project into grille slots. Thus, the flow regulator can be rotated by turning the grille.
The outer rim of the housing, on which the grille rests, and the outer surface of the grille have mating rings of shallow, generally V-shaped teeth. The grilles will not rotate if a weight such as a person or a piece of furniture is on the diffuser, but the teeth are designed to allow the grille to be rotated, thereby adjusting the air flow rate, with gentle manual pressure.
The mounting system for the diffuser includes a trim ring that extends through a hole in the floor and a retaining ring. The trim ring has a rim that rests on the floor. The retainer ring is shaped so that it can be dropped through the hole in the floor and then pulled up onto the trim ring, with the floor gripped between the retaining ring and the rim of the trim ring. The preferred retainer ring is movably fixed to the trim ring by a ratchet-like latching mechanism that allows the retainer ring to be rotated about and onto the trim ring. This accommodates various thicknesses of flooring panels. Once the trim ring is properly positioned, the retainer ring is ratcheted onto the trim ring to securely attach the diffuser to the floor.
The grille and the trim ring, or another stationary component of the diffuser that is mounted above the floor, have first and second indicators, respectively, that provide a visual indication of the position of the regulator. One of these indicators may be a pointer and the other may provide an approximate indication of the volumetric flow rate through the diffuser at different positions of the flow regulator. The relationship of one indicator to the other gives the user an immediate visual indication that the regulator is fully closed, fully open or at some intermediate position.
Other features and advantages to this invention will be apparent from the following description.